http://www.historyguy.com/comicshistory/captain_america_villains.htm
Captain America is an iconic hero for the the ages. And, as with many heroes in the comic world, he is often defined by the villains he faces and battles as much as by his own character. In the case of Captain America, who is also known as the First Avenger, and as the Sentinel of Liberty, his character often defines the types of villains he deals with.
As a living emblem of American pride, the American sense of justice and a true believer in American freedom and liberty, Captain America often, and naturally, finds his duty as defeating the enemies of justice, freedom, and liberty. Hence, Captain America’s personal Rogues Gallery is chock full of fascists, tyrants, wouldd-be dictators and genocides. Perhaps unusual for the world of comic superheroes, Captain America’s greatest foe is a real-life villain, the Nazi tyrant, Adolf Hitler. When Timely Comics published its first issue of Captain America Comics, the cover featured the Star-Spangled Avenger punching out Adolf Hitler himself. And this was BEFORE America entered World War Two!
Here is a Rogues Gallery of Captain America’s Greatest Villians and Foes:
Adolf Hitler: The leader of the world’s worst tyranny, Hitler was Captain America’s first target. Hitler (in the comics), commanded the allegiance of several Nazi/Fascist Supervillians who became life-long enemies of Captain America. 1st Appearance,(Timely/Marvel), Captain America Comics #1 (1941)
Red Skull (Johann Shmidt): Leader of HYDRA, the Red Skull was a Nazi villain working for Hitler in World War Two. After the war, the Red Skull continued his villainy and is counted as Captain America’s worst enemy. NOTE: the Red Skull’s power is greatly amplified when he has possessiono of the Cosmic Cube. 1st Appearance,Captain America Comics #7 (1941)
Baron Zemo I (Heinrich Zemo): Nazi war criminal from World War Two, Baron Zemo founded the Masters of Evil after the war and Zemo and his Masters of Evil became major foes of Captain America and his new team, the Avengers. 1st Appearance, Avengers #4, Vol.1 (1964)
Baron Zemo II (Helmut Zemo): Son of Baron Heinrich Zemo, Helmut Zemo formed his own versions the Masters of Evil in order to exact revenge on Captain America and the Avengers, whom he blamed for his father’s death. Helmut Zemo also, like his father, had pretensions of glory and sought world domination. 1st Appearance, Captain America #168 (1973)
Baron Wolfgang von Strucker – Nazi war criminal from World War Two, Baron von Strucker took over leadership of HYDRA and continued as a major foe of Captain America in the modern age. Also known as the Supreme Hydra. 1st Appearance, Sgt. Fury and his Howling Commandos #5 (1964)
HYDRA: Terrorist organization that seeks world domination. HYDRA has origins in Nazi Germany and has a Fascistic philosophy. Leaders have included the Red Skull, and Baron Von Strucker. 1st Appearance, Strange Tales #135 (Aug 1965)

Captain America Movie Poster